Piston pump actuating mechanism

ABSTRACT

A driving block is rigidly secured to and reciprocable with a pump piston rod. The driving block has a sliding block reciprocable therein, and a crank of a crankshaft is rotatable in the sliding block to convert rotary motion of the crankshaft into reciprocating movement of the piston rod. The sliding and driving blocks are shaped and arranged so that the rigid connection of the piston rod to the driving block is all that is needed to guide the driving block in its movement.

[ July 25, 1972 United States Patent Lennon S m M m n mm mm m T M U w wG N o A U T C A MM S m mm Tc E PM o w Inventor: Andrew Gordon Lennon,Dollard des 0rmeaux, Quebec, Canada ml .mk. aw DD mm 99 ll 91 1 Mn 91 67900 3,374,683 3/1968 Jesse..... 2,843,811 7/1958 [73] Asuignee: CraneCanada Limited, Montreal,

Quebec, Canada Nov. 25, 1970 Pn'mary Examiner--\Villiam F. ODeaAssistant Examiner-Wesley S. Ratliff, .l r. Attorney-Fatherstonhaugh &Co.

22 Filed:

[21] App]. No.:

ABSTRACT A driving block is rigidly secured to and reciprocable with a[30] Foreign Application Priority Data pump piston rod. The drivingblock has a sliding block reciprocable therein, and a crank of .acrankshaft is rotatable in the sliding block to convert rotary motion ofthe crankshaft into reciprocating movement of the piston rod. Thesliding and driving blocks are shaped and arranged so that the rigidconnection of the piston rod to the driving block is all that is neededto guide the driving block in its movement.

2 Claims, 5 Drawing Figures 4 082 0 9 0 h a 6 n 1 m Fm an m m d n u a un n n u a a n C m m Mb 1 W d t S ll c cl e 0 Uh. 1]] 2 8 55.5 [[lPatented July 25, 1972 2 Sheets-Sheet l INVENTOR A. s. LENNON WW VPATENT AGENTS PISTON PUMP ACTUATING MECHANISM This invention relates tonew and useful improvements in mechanisms for converting rotary intoreciprocating motion, and in particular the invention concerns itselfwith a mechanism of this type which is especially suitable for actuatinga reciprocating piston pump. I

The principal object of the invention is to provide a very simple pumpactuating mechanism which utilizes a minimum number of moving partsarranged to operate with a very low coefficient of friction and withoutundue eccentric forces or lateral stresses. Consequently, the mechanismof the invention eliminates the need for providing massive guides forthe moving parts, yet is durable and highly efiicient in operation andlends itself to economical manufactures.

With the foregoing more important object and features in view andsuch-other objects and features which may become apparent as thisspecification proceeds, the invention will be understood from thefollowing description taken in conjunction with the accompanyingdrawings, in which like characters of reference designate like parts,and wherein:

FIG. 1 is an exploded perspective view, partly in section, showingcomponents of the mechanism of the invention and also showing a drivingmotor and a pump by dotted lines;

FIG. 2 is a fragmentary horizontal sectional view of the assembledmechanism;

FIG. 3 is a fragmentary vertical sectional view, taken substantially inthe plane of the line 3-3 in FIG. 2;

FIG. 4 is an enlarged, fragmentary sectional detail, taken substantiallyin the plane of the line 4-4 in FIG. 3; and

FIG. 5 is a sectional detail, taken substantially in the plane of theline 5-5 in FIG. 4.

Referring now to the accompanying drawings in detail, the inventionconcerns itself with a mechanism for converting rotary intoreciprocating motion and is particularly suitable for actuating areciprocating piston pump by a prime mover, such as for example anelectric motor 11.

The mechanism of the invention comprises a housing 12 which includes amain housing portion 13 provided with a removable side plate 14. Thelatter is attached to the housing by suitable screws 15 and a gasket 16is interposed between the housing and the side plate to prevent leadageof oil which 1 is contained in the housing portion 13 to lubricate themechanism therein, as hereinafter described.

The housing 12 also includes an open frame-like extension 17 at one sideof the housing portion 13 and a pair of depending leg members 18 formounting the entire device on suitable supporting structure (not shown),as for example, a floor, a work bench, a vehicle chassis, or the like.Conveniently, the housing components 13, 17 and 18 may be formedintegrally as a unitary casting.

The frame-like extension 17 of the housing 12 serves to support the pump10 so that the pump is mounted at one side of the housing and issupported thereby. In the example shown, the housing extension 17 isprovided with an opening 19 which serves as a locating opening for acircular boss 20 at one side of the pump 10, and apertures 21 in theextension 17 receive screws (not shown) which extend into threaded bores22 in the pump and thus secure the pump to the housing extension 17. Theboss 20 of the pump 10 is concentric with a reciprocabl e piston .rod 23of the pump. The piston rod 23 passes through the housing extension 17into the closed housing portion 13 through a tubular guide or bearing 24which is mounted in the side wall of the housing portion 13 adjacent theextension 17, as will be apparent from FIGS. 1, 2 and 3. The piston rod23 is reciprocable in the guide 24 in order to actuate the pump 10.

The pump actuating mechanism of the invention comprises a driving block25 which is rigidly secured to the inner end portion of the piston rod23 which projects through the guide 24 into the housing chamber orportion 13. For example, the inner end portion of the rod 23 may bescrew-threaded into one side of the driving block 25 and secured by alock nut 26, so that the driving block is rigid with the piston rod andreciprocable therewith. The block 25 is provided with an open-ended bore27 in which is reciprocable a cylindrical sliding block 28. The lengthof the block 28 is substantially the same as that of the block 25 andwhen the block 28 reciprocates in the block 25, the block 28 projects tosome extent alternately from the open ends of the bore 27, but asufficient length of the sliding block 28 always remains in the bore 27to afford an adequate guiding action by the block 25 for the block 28.

The driving block 25 is provided at one side thereof with a slot 29which communicates with the bore 27, and a crank 30 of a crankshaft 31extends through the slot 29 into a bore 32 which is formed in thesliding block 28 at right angles to the longitudinal axis of the latter.The crankshaft 31 is rotatably journalled in a pair of bearings 33 inthe housing side plate 14, and after projecting outwardly from thehousing through the side plate, the crankshaft carries a combined drivepulley and flywheel 34 which is secured thereto by a set screw 35.

It will be apparent that when the crankshaft 31 is rotated by the pulley34, the crank 30 will cause the sliding block 28 to reciprotatevertically in the bore 27 of the driving block 25 as indicated at 36 inFIG. 3, and the driving block 25 with the sliding block 28 therein willbe reciprocated horizontally as indicated at 37. The horizontalreciprocation of the driving block 25 will be accompanied byreciprocation of the piston rod 23 to actuate the pump 10.

It is particularly significant to note that the oil bath in the housingportion or chamber 13 enables the crank 30 to rotate in the bore 32 ofthe sliding block 28 and the block 28 to slide in the bore 27 of thedriving block 25 with a very low coefficient of friction. This isfurther enhanced by the cylindrical shape of the sliding block 28 and ofthe bore 27 in the driving block 25. Moreover, since the block 28 at theends of its reciprocating stroke protrudes from the open ends of thebore 27 in the block 25, it is possible to make the length of the blocks25 and 28 substantially equal and relatively small in proportion to thestroke of the block 28. The relatively small blocks are thus light inweight and generate only very low centrifugal forces and lateralstresses during their movement. Consequently, the rigid connection ofthe piston rod 23 to the driving block 25 is all that is necessary toeffectively guide the driving block 25 in its movement. This eliminatesthe need for separate guides which are needed in conventionalmechanisms, and by eliminating such separate guides, the mechanisms ofthe invention is'not only simpler and more economical in construction,but also more efiicient in operation in that it eliminates friction atthe separate guides and thus facilitates more power to be used foractuation of the pump.

It is to be also noted that the arrangement of the invention makes itpossible to quickly and easily dis-assemble the mechanism for purposesof inspection or repair. All that is necessary is to remove the bolts 15which hold the housing side plate 14 in place, whereupon the side plate14 with the crankshaft 31 and pulley 34 may be bodily separated from thehousing 12 while the pulley 34 still remains attached to the crankshaft.As this separation occurs, the crank 30 of the crankshaft is simplywithdrawn from the bore 32 in the sliding block 28 through the slot 29in the driving block 25. The block 28 may then be easily slipped out ofthe bore 27 in the block 25 and the block 25 itself readily removed byunscrewing the same from the end of the piston rod 23 after the lock nut26 is loosened. Manifestly, the components may be reassembled with equalease and expediency.

Referring again to FIG. I, in addition to supporting the pump 10, thehousing 12 also supports the drive motor 11. In this regard, the motoris provided at one side thereof with a base member 36 which is pivotallyattached to a pair of upstanding lugs 37 on top of the housing extension17. A base member 38 at the other side of the motor is equipped with anadjustable screw 39 which bears against the top of the housing 12. Themotor armature 40 carries a pulley 41 which drives the pulley 34 throughthe medium of an endless belt 42, the

latter being pre-tensioned or pre-adjusted as to tension by adjustmentof the screw 39 in the conventional manner.

It will be apparent from the foregoing that the motion convertingmechanism of the invention, with its housing which also serves to mountthe drive motor and the pump, is a very simple and highly compact entitywhich efiiciently fulfills its intended purpose and may be convenientlyserviced when necessaryv While in the foregoing there has been shown anddescribed the preferred embodiment of the invention, variousmodifications and equivalents may be resorted to within the spirit andscope of the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows.

1. In a reciprocating piston pump actuating mechanism, the combinationof a housing, a pump piston rod linearly reciprocable in said housing, adriving block rigidly secured to said piston rod and linearlyreciprocable therewith, said driving block being provided with anopen-ended cylindrical bore having its axis at right angles to the lineof reciprocation of the driving block and also being provided in oneside thereof with a slot parallel to and communicating with said bore, acylindrical sliding block reciprocable in said bore of the drivingblock, a crankshaft journalled in said housing for rotation about anaxis normal to said piston rod, said crankshaft having a crank extendingthrough said slot in the driving block and rotatably engaging saidsliding block, and means for rotating said crankshaft, the rigidconnection of said driving block to said piston rod constituting solemeans for guiding the reciprocating movement of the driving block andthe driving block constituting sole means for retaining the slidingblock assembled on said crank.

2. The mechanism as defined in claim I which is further characterized inthat said driving block and said sliding block are of substantially thesame length, whereby the sliding block projects outwardly from said borein the driving block at the ends of its reciprocating movement in saidbore.

i I l i

1. In a reciprocating piston pump actuating mechanism, the combinationof a housing, a pump piston rod linearly reciprocable in said housing, adriving block rigidly secured to said piston rod and linearlyreciprocable therewith, said driving block being provided with anopen-ended cylindrical bore having its axis at right angles to the lineof reciprocation of the driving block and also being provided in oneside thereof with a slot parallel to and communicating with said bore, acylindrical sliding block reciprocable in said bore of the drivingblock, a crankshaft journalled in said housing for rotation about anaxis normal to said piston rod, said crankshaft having a crank extendingthrough said slot in the driving block and rotatably engaging saidsliding block, and means for rotating said crankshaft, the rigidconnection of said driving block to said piston rod constituting solemeans for guiding the reciprocating movement of the driving block andthe driving block constituting sole means for retaining the slidingblock assembled on said crank.
 2. The mechanism as defined in claim 1which is further characterized in that said driving block and saidsliding block are of substantially the same length, whereby the slidingblock projects outwardly from said bore in the driving block at the endsof its reciprocating movement in said bore.